In modern petroleum fields, fluid flow is controlled using downhole valves known as intelligent completions. An intelligent completion is a variable orifice valve. These valves may be adjusted at will. Typically, intelligent completions are deployed to control flow resistances at various zones in a well or system of wells, which is illustrated in FIG. 1. Generally, the aim is to deploy a combination of valves and sensors in the various production zones of a well to adjust flow distributions along the well-bore, either to achieve a desired fluid-front movement or to maintain a desired production or for conformance. The control strategy may be designed based on either pressure or flow-rate control. A detailed discussion of control strategies based on intelligent completions may be found in T. S. Ramakrishnan, “On reservoir Fluid-Flow with Smart Completions”, SPE84219, SPE Annual Technical Conference and Exhibition, 2003, which is entirely incorporated herein by reference.
Intelligent completion valves may be controlled from surface equipment or from controllers deployed in the downhole equipment. Other components are sensors for measuring pressure or flow-rate computer based controllers. Using a control algorithm in response to measured values, control the pressure or flow-rate by manipulating the valves to achieve a desired set point. The control algorithm, which is usually a feed-back controller, accepts a measured value as input and adjusts the valves in an effort to move the measured value towards the desired set point.
Usually control systems are designed for stability using a variety of methods, for example, those discussed in Process Dynamics, Modeling and Control by B. A. Ogunnake, W. H. Ray, 1994 and Process Systems Analysis and Control by Coughanowr, D. R., 1991. Downhole flow control is not amenable to standard linear theories. Therefore, the control system hardware used with a particular formation is designed based on simulations with the objectives of robustness and stability. After the control system has been deployed downhole to adjust flow within a formation, the control algorithm may be updated from the surface equipment or even remotely. The updates may include changing control parameters such as update time and sensitivity, for example, in response to measured production and injection data. A detailed discussion of intelligent completion systems may be found in Ramakrishnan, T. S., “On reservoir fluid-flow control with smart completions”, SPE Paper SPE84219, SPE Annual Technical Conference and Exhibition, 2003 (Society of Petroleum Engineers).
Any networked computer system is inherently vulnerable to security threats. In the oilfield, such threats are compounded by many factors, including their importance to national and international economies their high monetary value, and the expense associated with exploration, extraction and production equipment.
These factors also contribute to, at least, the following specific threats to intelligent completion systems:                Unauthorized operation of an intelligent completions installation        Use of unauthorized equipment with an intelligent completions control system        Theft of intelligent completions systems        Theft of proprietary parameter settings and algorithms used to control an intelligent completions system        
From the foregoing, it will be apparent that there is a need for an improved method to secure intelligent completions systems thereby overcoming foresaid security risks.